Uses and interpretation
The S&P/ASX 200 VIX is primarily used as an indicator of investor sentiment and market expectations. A volatility index at relatively high levels generally implies a market expectation of very large changes in the S&P/ASX 200 over the next 30 days, while a relatively low volatility index value generally implies a market expectation of very little change.
Similarly, when the volatility index is at relatively high levels and market expectation is for high levels of volatility, investor sentiment is perceived to be uncertain. Conversely, when the volatility index is at relatively low levels, market expectation is for low levels of volatility which implies greater levels of investor confidence.
Volatility indicators such as the S&P/ASX 200 VIX are often perceived to exhibit characteristics of mean reversion by oscillating around a long term average (or mean). In other words, a move away from the long term average towards high or low extremes is usually followed by a move back towards the long term average. The implication of mean reversion is that high levels of volatility are followed by a return to more normal levels of volatility and very low levels of volatility are often pre-cursors to an increase in volatility.
The S&P/ASX 200 VIX value is similar to rate of return volatility with the volatility index reported as an annualised standard deviation percentage that can be converted to a shorter time period. For instance, a volatility index value of 20% can be converted to a monthly figure remembering that volatility scales at the square root of time. The formula to do this is: